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Soils of the Gulf Islands of British Columbia Volume 2 Soils of North Pender, South Pender Prevost, Mayne, Saturna, and lesser islands Report No. 43 British Columbia Soi1 Survey E.A. Kenney, L.J.P. van Vliet, and A.J. Green B.C. Soi1 Survey Unit Land Resource Research Centre Vancouver, B.C. Land Resource Research Centre Contribution No. 86-76 (Accompanying Map sheets from Soils of the Gulf Islands of British Columbia series: * North Pender, South Pender, and Prevost islands + Mayne and Saturna islands) Research Branch Agriculture Canada 1988 Copies of this publication are available from Maps B.C. Ministry of Environment Parliament Buildings Victoria, B.C. vav 1x5 o Minister of Supply and Services Canada 1988 CAt. No.: A57-426/2E ISBN: O-662-16258-7 Caver photo: Boot Cave, Saturna Island, looking towards Samuel Island. Courtesy: Province of British Columbia Staff editor: Jane T. Buckley iii CONTENTS Page ACKNOWLEDGMENTS. vii . PREFACE. ..Vlll PART 1. INTRODUCTION............................................. 1 PART 2. GENERALDESCRIPTION OF THE AREA.......................... 3 Location and extent ............................................ 3 History and development ........................................ 3 Climate ........................................................ 11 Natural vegetation ............................................. 11 Geology ........................................................ 15 Physiography ................................................... 16 Soi1 parent materials .......................................... 16 PART 3. SURVEY AND MAPPING PROCEDURES............................ 20 How the soils were mapped...................................... 20 Data handling .................................................. 21 Reliability of mapping ......................................... 22 Soi1 series .................................................... 22 Map units ...................................................... 24 PART 4. DESCRIPTION OF SOILS AND MAP UNITS ....................... 29 Description of soils .............................................. 29 Description of map units .......................................... 30 Baynes soils and map units ........................................ 31 Beddis soils and map units ........................................ 33 Bellhouse soils ................................................... 36 Brigantine soils and map units .................................... 39 Cowichan soils and map units ...................................... 43 Crofton soils and map units ....................................... 45 Fairbridge soils and map units .................................... 48 Galiano soils and map units ....................................... 51 Haslam soi1 complex and map units ................................. 55 Metchosin soils and map units ..................................... 58 Mexicana soils and map units ...................................... 61 Neptune soi1 and map unit ......................................... 64 Parksville soils and map units .................................... 66 Pender Island soi1 complex and map units .......................... 69 Qualicum soils and map units ...................................... 72 iv Page Rock as nonsoil and map units ..................................... 75 Salalakim soils and map units ..................................... Saturna soils and map units ....................................... 8'1" St. Mary soils and map units ...................................... 85 Tolmie soils and map units ........................................ 88 Trincomali soils and map units .................................... 90 Summary of areal extent of map units in survey area ............... 93 PART 5. LAND USE INTERPRETATIONS. 95 Land constraints for septic tank effluent absorption .............. 95 Land capability for agriculture ................................... 101 PART 6. DERIVED AND INTERPRETIVE MAPS. 109 REFERENCES. 110 APPENDIXES Appendix 1. Profile descriptions and analytical data of the soils . 116 Appendix 2. Soi1 moisture data for the soi1 profiles............. 135 V LIST OF TABLES AND ILLUSTRATIONS TABLES Page 1. SUmmary of climatic data for the southern Gulf Islands . 12 2. Mean temperatures and precipitation for Mayne and North and South Pender islands . .. 13 3. Number of delineations and areal extent of each map unit and land type . 26 4. Number of delineations and areal extent of each map unit and land type for North Pender, South Pender, and Prevost islands map sheet . 27 5. Number of delineations and areal extent of each map unit and land type for Mayne, Saturna, and lesser islands map sheet . 28 6. Distribution of map units in survey area by origin of parent material . 94 7. Constraint classes and soi1 and landscape limitations for septic tank effluent absorption........................ 97 8. Land capability ratings for agriculture.................... 103 FIGURES 1. Locations of North and South Pender, Prevost, Mayne, Saturna, and lesser islands in relation to the Gulf Islands and the Province of British Columbia............... 4 2. North and South Pender islands . 8 3. Prevost Island . 8 4. Mayne Island . 9 5. Saturna Island . 9 6. Mean monthly precipitation: for (a) North Pender, (b) South Pender, and (c) Mayne islands.................... 14 7. Extreme precipitation for North Pender Island.............. 14 8. Generalized cross section of soi1 parent materials and typical soils in relation to landscape position........ 17 9. Inspection density and relative mapping accuracy for North and South Pender and Prevost islands............. 23 vi PLATES Page 1 (a) Pasture on Mayne Island, (b) second-growth toast Douglas fir, (c) Mount Warburton Pike Peak, Saturna Island, (d) typical rock - shallow soils landscape, (e) profile of shallow Saturna soil, (f) pasture on Prevost Island . 5 II (a) narrow drainageway landscape, (b) Tolmie soi.1 profile, (c) Metchosin soi1 landscape, (d) Metchosin soi1 profile, (e) Bellhouse soi1 landscape, (f) Bellhouse soi1 profile....................... 6 vii ACKNOWLEDGMENTS Assistance and support were provided by the following agencies and individuals: T.M. Lord, previous Head, British Columbia Pedology Unit, Agriculture Canada, Vancouver, who directed the soi1 survey; G. Clark, A. Candy, J. Rowed, and G. Davies who assisted in the field mapping; L. Chan, who conducted the laboratory analyses; J. Melzer, who typed the manuscript; Cartography Section, Land Resource Research Centre, Agriculture Canada, Ottawa, Ont., which provided base maps, drafted the figures, and prepared the final soi1 maps; and G. Enguist and M. Botting, Cartographie Services Unit, Surveys and Resource Mapping Branch, British Columbia Ministry of Environment, Victoria, who drafted and prepared interim soi1 maps and legends. Pedologist J. Jungen, Surveys and Resource Mapping Branch, British Columbia Ministry of Environment, Victoria, provided much help with soi1 correlation and agriculture capability ratings; and C. Tarnocai, Land Resource Research Centre, Ottawa, Ont., kindly reviewed the manuscript and the map legends. viii PREFACE North and South Pender, Prevost, Mayne, Saturna, and lesser islands caver a total area of 10 280 ha in the Gulf Islands of British Columbia shown on map sheets 92B/ll and 92B/14 of the National Topographie Series. The aim of this report is to provide detailed soils information at a scale of 1:20 000 for local planning purposes, and to emphasize the soi1 limitations that are important to residential development and agriculture. The two accompanying soi1 maps show the distribution and extent of the soi1 map units. The map legends identify each map unit by color and symbol. Each gives the proportion of dominant, subdominant, or minor soi1 components, the origin and texture of the parent materials, the soi1 depth, the soi1 drainage, and the landscape characteristics for each map unit. The report and map are complementary; therefore, it is necessary to use both to fully understand the soils. Two interim soi1 maps with extended legends have also been produced at a 1:20 000 scale and have been made available from the Map Library, Maps B.C., Ministry of Environment, Victoria, B.C. Note: This publication is the second in a series of five volumes on Soils of the Gulf Islands of British Columbia, Report No. 43 of the British Columbia Soi1 Survey. The other publications are entitled: Volume 1 Soils of Saltspring Island; Volume 3 Soils of Galiano, Valdes, Thetis, Kuper, and lesser islands; Volume 4 Soils of Gabriola Island and lesser islands; and Volume 5 Soils of Sidney, James, Moresby, Portland, and lesser islands. The correct citation is as follows: Kenney, E.A.; Van Vliet, L.J.P.; Green, A.J. 1988. Soils of the Gulf Islands of British Columbia: Volume 2 Soils of North Pender, South Pender, Prevost, Mayne, Saturna, and lesser islands. Report No. 43, British Columbia Soi1 Survey. Research Branch, Agriculture Canada, Ottawa, Ont. 137 PP* -l- PART 1. INTRODUCTION The first soi1 survey that included the Gulf Islands was completed in the late 1950s (Day et al. 1959). This survey at a scale of 1:63 360 (2.5 cm to 1.6 km) served a useful purpose for land planners and agriculturists over the years. During the Canada Land Inventory mapping program in the 1960s more soils information was obtained for the Gulf Islands to produce capability maps for agriculture and other uses (1:50 000). Since then, some of the Gulf Islands have been surveyed in more detail by different agencies in response to requests from